From: Thomas Huth <thuth@redhat.com>
To: Cornelia Huck <cohuck@redhat.com>,
Matthew Rosato <mjrosato@linux.ibm.com>
Cc: "Alex Williamson" <alex.williamson@redhat.com>,
"Pierre Morel" <pmorel@linux.ibm.com>,
"David Hildenbrand" <david@redhat.com>,
"Richard Henderson" <richard.henderson@linaro.org>,
qemu-devel@nongnu.org, "Halil Pasic" <pasic@linux.ibm.com>,
"Christian Borntraeger" <borntraeger@de.ibm.com>,
qemu-s390x@nongnu.org,
"Philippe Mathieu-Daudé" <philmd@redhat.com>
Subject: Re: [PATCH for-5.2] s390x/pci: fix endianness issues
Date: Tue, 17 Nov 2020 20:21:51 +0100 [thread overview]
Message-ID: <6a1b2ba1-642a-9cee-4d7d-2c1e4ea826ed@redhat.com> (raw)
In-Reply-To: <20201117171340.1289659-1-cohuck@redhat.com>
On 17/11/2020 18.13, Cornelia Huck wrote:
> zPCI control blocks are big endian, we need to take care that we
> do proper accesses in order not to break tcg guests on little endian
> hosts.
>
> Fixes: 28dc86a07299 ("s390x/pci: use a PCI Group structure")
> Fixes: 9670ee752727 ("s390x/pci: use a PCI Function structure")
> Fixes: 1e7552ff5c34 ("s390x/pci: get zPCI function info from host")
This fixes the problem with my old Fedora 28 under TCG, too, but... do we
really want to store this information in big endian on the QEMU side (e.g.
in the QTAILQ lists)? ... that smells like trouble again in the future...
I think it would be better if we rather replace all those memcpy() functions
in the patches that you cited in the "Fixes:" lines above with code that
changes the endianess when we copy the date from QEMU space to guest space
and vice versa. What do you think?
Thomas
next prev parent reply other threads:[~2020-11-17 19:23 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-17 17:13 [PATCH for-5.2] s390x/pci: fix endianness issues Cornelia Huck
2020-11-17 17:59 ` Philippe Mathieu-Daudé
2020-11-17 18:19 ` Matthew Rosato
2020-11-17 18:30 ` Philippe Mathieu-Daudé
2020-11-17 18:39 ` Thomas Huth
2020-11-17 18:49 ` Philippe Mathieu-Daudé
2020-11-17 19:23 ` Thomas Huth
2020-11-17 19:20 ` Matthew Rosato
2020-11-17 19:21 ` Thomas Huth [this message]
2020-11-17 19:49 ` Matthew Rosato
2020-11-18 7:49 ` Cornelia Huck
-- strict thread matches above, loose matches on Subject: below --
2020-11-18 8:51 Cornelia Huck
2020-11-18 8:53 ` Cornelia Huck
2020-11-18 9:38 ` Thomas Huth
2020-11-18 10:19 ` Cornelia Huck
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